The Sungai Piah Hydroelectric Project is located in the State of Perak in Peninsular Malaysia. It is a run-of-river project on steep mountain streams in dense tropical jungle. Nine intakes, of various sizes and design, supply water via 23km of tunnels and two vertical shafts, to two high-head, remotely controlled power stations in cascade. Site roads totalling 96km had to be constructed to obtain access to the various structures. Establishing an accurate ground control survey network over the wide-spread project area was one of the major problems. Deep tropical weathering greatly restricted geological mapping, particularly along river beds which were frequently affected by paleo slides. Difficult and limited access permitted only a minimum amount of subsurface exploration to be undertaken at the feasibility stage. Other techniques, especially to evaluate tunnel conditions, were successfully implemented. This paper deals mainly with the difficulties encountered and logistics required from feasibility to the implementation of construction.